U.S. patent number 4,990,280 [Application Number 07/322,636] was granted by the patent office on 1991-02-05 for photoactivator dye composition for detergent use.
This patent grant is currently assigned to Danochemo A/S, The Proctor & Gamble Co.. Invention is credited to Bitten Thorengaard, David W. York.
United States Patent |
4,990,280 |
Thorengaard , et
al. |
February 5, 1991 |
**Please see images for:
( Certificate of Correction ) ** |
Photoactivator dye composition for detergent use
Abstract
A photoactivator dye composition includes microcapsules of a
solid dispersion of a water-soluble photoactivator dye in an
encapsulating material that is quickly soluble in water. In a
method of preparing such a photoactivator dye composition, the
photoactivator dye is dissolved in an aqueous medium, the solution
thus obtained is mixed with an aqueous solution of the
encapsulating material, the mixture thus obtained is converted into
droplets, and the moisture content of these droplets is reduced to
form a solid solution. The photoactivator dye composition may
advantageously be used in a detergent composition which
additionally includes a surfactant and conventional detergent
ingredients.
Inventors: |
Thorengaard; Bitten
(Charlottenlund, DK), York; David W. (Waterloo,
BE) |
Assignee: |
Danochemo A/S (Ballerup,
DK)
The Proctor & Gamble Co. (Cincinnati, OH)
|
Family
ID: |
10633392 |
Appl.
No.: |
07/322,636 |
Filed: |
March 13, 1989 |
Foreign Application Priority Data
|
|
|
|
|
Mar 14, 1988 [GB] |
|
|
8806016 |
|
Current U.S.
Class: |
510/301; 8/103;
427/213.35; 516/70; 516/72; 427/213.3; 428/403; 510/349;
510/441 |
Current CPC
Class: |
C11D
3/40 (20130101); C11D 3/0063 (20130101); C11D
17/0039 (20130101); Y10T 428/2991 (20150115) |
Current International
Class: |
C11D
17/00 (20060101); C11D 3/00 (20060101); C11D
003/40 (); C11D 003/395 (); B01J 013/04 () |
Field of
Search: |
;252/94,95,90,174,315.1,315.3,174.13 ;8/103,107 ;428/403
;427/213.3,213.35 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Willis; Prince E.
Attorney, Agent or Firm: Watson, Cole, Grindle &
Watson
Claims
What is claimed is:
1. A photoactivator dye composition comprising microcapsules of a
solid dispersion of a water-soluble photoactivator dye in an
encapsulating material that is quickly soluble in water, said
microcapsules comprising, by weight of the capsules,
(a) from 1% to 60% of the photoactivator dye,
(b) from 38% to 97% of an encapsulating material selected from the
group consisting of gelatine, hydrolyzed gelatine and film-forming
carbohydrates, and
(c) from 2% to 12% water.
2. A composition as in claim 1, wherein the encapsulating material
is insoluble in nonionic surfactants.
3. A composition as in claim 1, comprising microcapsules having an
average particle size range of from 50 micrometers to 450
micrometers.
4. A composition as in claim 1, wherein the photoactivator dye is a
polyvalent metal ion complex of sulfonated phthalocyanine.
5. A composition as in claim 4, wherein the photoactivator dye is
at least one sulfonate selected from the group consisting of zinc
phthalocyanine sulfonate and aluminium phthalocyanine
sulfonate.
6. A composition as in claim 1, wherein the encapsulating material
is selected from the group consisting of hydrolyzed gelatine and
film-forming carbohydrates.
7. A composition as in claim 6, wherein said encapsulating material
is a film-forming carbohydrate selected from the group consisting
of dextrin and gum Arabic.
8. A composition as in claim 1, wherein the microcapsules comprise
from 1 to 40% by weight of the photoactivator dye.
9. A composition as in claim 1, which further contains saccharose
or glucose syrup, the weight ratio of encapsulating material to
sugar being at least 35:65.
10. A composition as in claim 9, wherein the weight ratio of
encapsulating material to sugar is 50:50.
11. A detergent composition which comprises 2 ppm to 1,000 ppm,
based on the total weight of the detergent composition, of a
photoactivator dye composition that comprises microcapsules of a
solid dispersion of a water-soluble photoactivator dye in an
encapsulating material that is quickly soluble in water, said
microcapsules comprising, by weight of the capsules,
(a) from 1% to 60% of the photoactivator dye,
(b) from 38% to 97% of an encapsulating material selected from the
group consisting of gelatine, hydrolyzed gelatine and film-forming
carbohydrates, and
(c) from 2% to 12% water.
12. A detergent composition as in claim 11 which comprises from 1%
to 12% of a nonionic surfactant.
13. A detergent composition as in claim 12, wherein the nonionic
surfactant comprises a mixture of alkoxylated alcohols of the
formula R(R'O)xOH, wherein R is hydrocarbyl having from 12 to 20
carbon atoms, R'O represents an alkoxy group and x ranges from 4 to
12.
14. A method of preparing a photoactivator composition which
comprises microcapsules of a solid dispersion of a water-soluble
photoactivator dye in an encapsulating material that is quickly
soluble in water, said microcapsules comprising, by weight thereof,
of 1 to 60% of photoactivator dye, 38-97% encapsulating material
selected from the group consisting of gelatine, hydrolyzed gelatine
and film-forming carbohydrates, and 2 to 12% water, comprising the
steps of
(1) dissolving the photoactivator dye in an aqueous medium,
(2) mixing the photoactivator dye solution with an aqueous solution
of the encapsulating material,
(3) converting the mixture thus obtained into droplets of an
average particle size not exceeding 500 micrometers, and
(4) reducing the moisture content of said particles to a value of
between 2% and 12% by weight to form a solid solution of the
photoactivator dye in the encapsulating material.
15. A method as in claim 14, wherein the conversion of the mixture
into droplets and reducing the moisture content of said droplets is
effected by spray-drying.
16. A method as in claim 15, wherein the spray-drying is effected
at a temperature of below 100.degree. C. while introducing a fine
powder into the spray-drying zone.
17. A method as in claim 15, wherein the spray-drying is effected
at a temperature of above 100.degree. C.
18. A method as in claim 14, wherein saccharose or glucose is added
to the mixture of the photoactivator dye and encapsulating
material.
19. A method as in claim 14, wherein an oil is emulsified in the
mixture of the photoactivator dye and encapsulating material.
Description
TECHNICAL FIELD
This invention relates to a photoactivator dye composition which is
particularly suitable for detergent use, a method for preparing
such a photoactivator composition and a detergent composition
comprising the same.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 3,927,967 discloses the use of photoactivator dyes
like phtalocyanine dyes for use in detergents. Such photoactivator
dyes are capable of absorbing electromagnetic radiation in the
visible light range and releasing the absorbed energy quanta in a
form that provides bleaching action on fabrics. It is believed that
the energy quanta form singlet oxygen which is oxidatively active.
Some photoactivators, like zinc phtalocyanine sulfonate (ZPS) and
aluminium phtalocyanine sulfonate (APS), have found commercial
application in granular detergent compositions.
However, when used in detergent compositions the phtalocyanine dyes
present certain drawbacks that have heretofore not properly been
addressed. One such drawback is that the particles in which the
dyes are incorporated do not dissolve sufficiently quickly when
contacted with water to avoid dye staining. Such contact is
particularly likely to occur in endwise situations and even when
the detergent composition containing the dye is dispensed from the
machine dispenser of a typical European washing machine.
It has been attempted to spray a solution of the dye onto
spray-dried detergent granules, but it has been found that the
granules thus treated do not dissolve quickly enough to avoid dye
staining of the fabric. The current trend is towards higher density
detergent granules which are even less suitable carriers for the
dye.
The best route of photoactivator dye addition available to date
comprises spraying a dye solution onto low density granules that
are subsequently dry mixed with the base granules of the detergent
composition. Although these low density granules dissolve more
quickly than the base granules they do not dissolve quickly enough
to prevent dye staining of fabrics under various laundering
conditions.
SUMMARY OF THE INVENTION
The present invention relates to phtalocyanine dyes for detergent
use, characterized in that the dyes are encapsulated in an
encapsulating material that quickly dissolves in cold water.
Preferably, the encapsulating material does not dissolve in
nonionic surfactant.
Preferred phtalocyanine dyes are zinc phtalocyanine sulfonate (ZPS)
and aluminium phtalocyanine sulfonate (APS).
Preferred encapsulating materials include gelatine, particularly
low bloom gelatines, and mixtures of gelatine and sugar.
The present invention also relates to a method for preparing
encapsulated photoactivator compositions, comprising the steps
of
1. dissolving the photoactivator dye in an aqueous medium,
2. mixing the photoactivator dye solution in an aqueous solution of
the encapsulating material,
3. converting the mixture then obtained into droplets of an average
size not exceeding 500 micrometers,
4. reducing the moisture content of the particles to a value of
between 2% and 12% by weight.
The invention further relates to granular detergent compositions
containing the encapsulated phtalocyanine dyes.
DETAILED DESCRIPTION OF THE INVENTION
The photoactivator dye composition according to the invention
comprises micro capsules of a solid solution of a water soluble
photoactivator dye (solute) in an encapsulating material (solvent)
that is quickly soluble in cold water, these microcapsules
comprising by weight of the capsules,
(a) from 1% to 60% of the photoactivator dye, preferably from 1% to
40%,
(b) from 38% to 97% of the encapsulating material, and
(c) from 2% to 12% water, preferably from 2% to 5%.
The term "microcapsules" means capsules having an average particle
size not exceeding 500 micrometers and preferably an average
particle size range of from 50 micrometers to 450 micrometers.
In order to evaluate a material's capability to quickly solubilize
in cold water, the following experiment can be performed.
A Sotax AT6 dissolution apparatus is used, in which the stirring
speed is set af 150 rpm, using the paddle stirrer bars. 1,000 mls
of ph 9.5 buffer is poured into each polycarbonate beaker, and
maintained at 20.degree. C. 0.05 g of material is added to the
buffer solution. While stirring under the specified conditions, 3
ml aliquots of the solution are withdrawn at 15 seconds intervals
for 2 minutes; the absorbance of each of the aliquots is measured
at 669 nm. According to this experiment, suitable materials have
the following dissolution profile:
.gtoreq.80% dissolved at 30 seconds,
.gtoreq.95% dissolved at 60 seconds,
100% dissolved at 120 seconds.
Preferably, the encapsulating material of the photoactivator dye
composition does not dissolve in nonionic surfactants. Indeed,
modern detergent compositions almost invariably contain nonionic
surfactants, typically at levels of from 1% to 12%. In most cases
this nonionic surfactant is sprayed onto the base granules of the
detergent composition. During storage the nonionic detergent freely
migrates through the bulk of the detergent composition,
particularly if the nonionic surfactant is liquid at the
temperature of storage.
Since phtalocyanine dyes are highly soluble in nonionic
surfactants, these dyes migrate as well and become absorbed to the
base granules rather than to the low density granules. The
appearance of the detergent composition becomes rather unattractive
as a result. Moreover, the dissolution of the dye becomes
associated with the dissolution of the base granules rather than
with the much faster dissolution of the low density granules.
The insolubility of the encapsulating materials in nonionic
surfactant, as required herein, can be evaluated in the following
expirement:
0.05 g of the encapsulating material is added to 50 ml Dobanol 45
E.sub.7 at 40.degree. C. (Dobanol 45 E.sub.7 is an alkyl alcohol
ethylene oxide condensate; it is predominantly linear C.sub.14
/C.sub.15 primary alcohol with an average of 7 ethylene oxide
groups).
The temperature is maintained at 40.degree. C. for 1 hour. The
dissolution is measured by the absorbance at 669 nm and, according
to this measure, there should be no sign of dissolution after 1
hour.
Examples of suitable water soluble photoactivators include eosin,
rose bengal, fluorescin, chlorophyll, metal-free porphyrin and
polyvalent metal ion complexes of sulfonated phtalocyanine,
especially when free of unsulfonated phtalocyanine.
Suitable examples of polyvalent metal ions include Zn.sup.2+,
Al.sup.3+, Mn.sup.2+, etc. Preferred photoactivator dyes are zinc
phtalocyanine sulfonate (ZPS) and aluminium phtalocyanine sulfonate
(APS). These dyes are commercially available as the sodium
salts.
In a preferred embodiment the microcapsules comprise from 5% to 30%
by weight of the photoactivator dye.
Examples of suitable encapsulating materials include gelatine,
hydrolyzed gelatine, film-forming carbohydrates. Preferred
encapsulating materials are hydrolyzed gelatine, and film-forming
carbohydrates including dextrin and gum Arabic.
The photoactivator dye composition described above can be prepared
by a method comprising:
(1) dissolving the photoactivator dye in an aqueous medium,
(2) mixing the photoactivator dye solution with an aqueous solution
of the encapsulating material,
(3) converting the mixture thus obtained into droplets of an
average particle size not exceeding 500 micrometer, and
(4) reducing the moisture content of the particles to a value of
between 2% and 12% by weight to form a solid solution of the
photoactivator dye in the encapsulating material.
The encapsulating material should preferably have a molecular
weight which is substantially higher than that of the
photoactivator dye. Thus, if the size of the molecules of the
photoactivator dye is less than about 0.6 of that of the
encapsulating material, an extensive interstitial solid solution,
i.e., a solid solution in which the solute molecules occupy the
interstitial space of the solvent lattice is obtained.
The formation of such an interstitial solid solution appears to
substantially contribute to a quick release of the photoactivator
dye in a finely dispersed form when the capsules are contacted with
water.
The conversion of the mixture into droplets and the reduction of
the moisture content of the droplets are preferably effected by a
spray-drying technique.
In a preferred embodiment of the method of the invention the
mixture is spray-dried at an elevated temperature of below
100.degree. C. while introducing a fine powder into the spray
drying zone, as explained in U.S. Pat. No. 2,756,177. The fine
powder can be silicate or, preferably, finely divided corn
starch.
In another preferred embodiment the mixture is spray-dried at a
temperature of above 100.degree. C.
In a preferred embodiment saccharose of glucose sirup can be added
to the mixture to be spray-dried in order to lower the viscosity of
the mixture, the weight ratio of encapsulating material to sugar
being at least 35:65, preferably 50:50.
Preferably an oil such as coconut oil is incorporated in the
mixture to be spray-dried in the form of an emulsion. The presence
of the oil facilitates the formation of droplets when the mixture
is spray-dried, and amounts of from 3% to 20% by weight, preferably
5% to 10% by weight can be used; the most preferred amount of oil
is 5% by weight.
The dry matter content of the mixture to be spray-dried may vary
within wide ranges, but the viscosity is preferably maintained
within the range of from 70 cp to 200 cp at 60.degree. C.
The detergent composition according to the invention preferably
contains the photoactivator dye composition described above in an
amount of from 2 ppm to 1,000 ppm of the pure photoactivator dye by
weight of the detergent composition.
The detergent composition further contains typical detergent
ingredients, e.g., organic surfactants, detergent builders,
conventional detergent adjuncts, etc.
Preferred detergent compositions are those containing from 1% to
12%, preferably from 3% to 10%, of a nonionic surfactant.
The preferred nonionic surfactant preferably comprises a mixture of
alkoxylated alcohols of the formula R(R'O)xOH, wherein R is
hydrocarbyl containing from 12 to 20 carbon atoms, R'O represents
an alkoxy group, preferably an ethoxy group and x ranges from 4 to
12.
The invention will now be described in further detail with
reference to the following examples.
EXAMPLES
Example 1
3,240 g gelatine (Bloom strength 0) and 3,240 g sugar were added to
a solution of 1,300 g zinc phtalocyanine sulfonate in 5,200 g water
while stirring. 650 g coconut oil were emulsified in the solution
thus obtained.
The dry matter content of the mixture thus prepared was about 60%,
about 16% being zinc phtalocyanine sulfonate and the viscosity was
96 cp at 55.degree. C.
The mixture was spray-dried in a spray drying tower while
simultaneously introducing corn starch therein as a powdering
composition.
The mixture was introduced at a rate of 2 l/min. and the
temperature of the spray drying zone was about 70.degree. C.
The final product (about 9,200 g) was sieved and the mesh 30--mesh
120 (ASTM) fraction was collected and analyzed. The collected
fraction contained 14.1% zinc phtalocyanine sulfonate and the
average particle diameter was about 350 micrometer.
Example 2
2,388 g gelatine was dissolved in 2,135 g water by stirring and
heating to a temperature of about 60.degree. C. A solution of 126 g
sodium hydroxide in 215 g water was added under stirring to the
gelatine solution at a temperature of 60.degree. C. After stirring
for 20 min. at 60.degree. C. 135 g concentrated sulfuric acid (96%)
was added and the pH-value was adjusted at about 5.5. 900 g of the
solution thus obtained (hydrolyzed gelatine) was mixed with a
solution of 100 g zinc phtalocyanine sulphonate in 1150 g water,
450 g spray-dried glucose syrup (MOR-SWEET.RTM. 1924) and 50 g
coconut oil while stirring at 55.degree. C. When the coconut had
been emulsified in the aqueous medium an additional amount of 700 g
water was added. The dry matter content of the mixture thus
obtained was about 30%, about 10% being zinc phtalocyanine
sulfonate. The viscosity of the mixture was about 50 cp at
60.degree. C. The mixture was spray-dried in a conventional
spray-drying tower at an inlet temperature of 240.degree. C. and an
outlet temperature of 97.degree. C.
The spray-dried product (about 900 g) was sieved and the sieve
fraction having a particle size of less than 100 mesh (ASTM) was
collected.
This fraction contained 9.7% zinc phtalocyanine sulfonate and the
average particle size was about 50 micrometer.
Example 3
A granular detergent composition was prepared, having the following
composition:
______________________________________ Ingredient %
______________________________________ tallow alkyl sulfate 2.4
linear alkyl benzene sulfonate 5.6 polymer 2.0 silicate 8.0 sodium
tripolyphosphate 21.0 sodium perborate 15.0 nonionic (DOBANOL .RTM.
45E.sub.7) 5.0 enzyme (protease) 0.8 TAED 2.0 zinc phtalocyanine
sulfonate* 0.03 minor (optical brightener, chelants, BALANCE CMC,
perfume, suds suppressor); inorganic salts (sodium sulfate, sodium
carbonate, magnesium sulfate); and water.
______________________________________ (*as encapsulates in
zerobloom gelatine, ZPS content of capsules 3.4%. Particle size of
the capsules 150-450 micrometers; 0.88% was added, to result in a
ZPS level in the detergent composition of 0.03.)
Example 4
1060 g gum Arabic and 1010 g sugar were added to a solution of 1375
g zinc phtalocyanine sulfonate in 1850 g water while stirring. 138
g coconut oil was emulsified in the solution thus obtained.
The dry matter content of the mixture thus prepared was about 45%,
about 11.4% being zinc phtalocyanine sulfonate and the viscosity
was 108 cp at 57.degree. C.
The mixture was spray-dried in a spray-drying tower while
simultaneously introducing corn starch therein as a powdering
composition.
The mixture was introduced at a rate of 1.5 /min. and the
temperature of the spray-drying zone was about 65.degree. C.
The final product (about 3500 g) was sieved and the mesh 30 --mesh
170 (ASTM) fraction was collected and analyzed.
The collected fraction contained 8.2% zinc phtalocyanine sulfonate
and the average particle diameter was about 250 micrometer.
Example 5
1060 g gelatine (Bloom strength 0) and 1010 g sugar were added to a
solution of 1250 g sulphonated aluminium tetrabenzotetraazaporphine
in 850 g water while stirring. 138 g coconut oil was emulsified in
the solution thus obtained.
The dry matter content of the mixture thus prepared was about 53%,
about 6.3% being aluminium tetrabenzotetraazaporphine and the
viscosity was 106 cp at 58.degree. C.
The mixture was spray-dried in a spray-drying tower while
simultaneously introducing corn starch therein as a powdering
composition.
The mixture was introduced at a rate of 1.5 l/min. and the
temperature of the spray-drying zone was about 70.degree. C.
The final product (about 2800 g) was sieved and the mesh 30 --mesh
170 (ASTM) fraction was collected and analyzed. The collected
fraction contains 5.2% aluminium tetrabenzotetraazaporphine.
Example 6
1060 g gum Arabic and 1010 g spray-dried glucose syrup
(MOR-SWEET.RTM. 1924) were added to a solution of 1250 g
sulphonated aluminium tetrabenzotetraazaporphine in 2350 g water
while stirring. 138 g coconut oil was emulsified in the solution
thus obtained.
The dry matter content of the mixture thus prepared was about 40%,
about 6.3% being aluminium tetrabenzotetraazaporphine and the
viscosity was 104 cp at 58.degree. C.
The mixture was spray-dried in a spray-drying tower while
simultaneously introducing corn starch therein as a powdering
composition.
The mixture was introduced at a rate of 1.5 l/min. and the
temperature of the spray-drying zone was about 70.degree. C.
The final product (about 3100 g) was seived and the mesh 30 --mesh
170 (ASTM) fraction was collected and analyzed. The collected
fraction contained 4.2% of aluminium
tetrabenzotetraazaporphine.
* * * * *